1. Field of the Invention
The present invention relates to an information processing apparatus which executes high-speed pattern identification of information, and a control method thereof.
2. Description of the Related Art
As a high-speed pattern identification method, various methods have been proposed so far. For example, in association with a target object discrimination method, Japanese Patent Laid-Open No. 2009-26326 has proposed a method of discriminating based on a feature amount based on the difference between pixel luminance values at two positions whether or not an input grayscale image is a target object. This method can attain high-speed pattern identification since it uses a high-speed weak classifier using sampling data in the input grayscale data, that is, pixel luminance values at two positions. However, with this method, the difference between the pixel luminance values at the two positions used as the feature amounts is robust against bias variations of luminance values, but it is not robust against, for example, contrast variations caused by shading.
In association with pattern identification which is robust against such contrast variations, for example, Japanese Patent Laid-Open No. 2009-43184 has proposed a method which attains pattern identification using an edge image generated by applying edge extraction to input grayscale image data. With this method, features such as edges are extracted in advance, and pattern identification processing is applied to that data, thus allowing pattern identification which is robust against various variations. However, feature amounts such as edges generally tend to form a coarse distribution. Therefore, since various pieces of combination information of sampling data have no significant differences, a sufficiently high pattern identification performance cannot be consequently obtained.
As described above, a pattern identification method, which is robust against, for example, contrast variations caused by shading in image data, and allows high-speed processing, is demanded.
The present invention provides, in consideration of the above situation, an information processing apparatus which identifies a specific pattern at high speed using sampling data in image data, and attains high-speed identification which is robust against various variations.